Control Of Ventilation

Question 1

What are the three factors involved in the regulation of pulmonary ventilation during exercise?

Answer 1

Neural control, chemical control and hormonal control

Question 2

Where is the respiratory centre located?

Answer 2

In the medulla oblongata

Question 3

What are the two main areas of the respiratory centre?

Answer 3

The inspiratory and expiratory centres

Question 4

What does the expiratory centre do?

Answer 4

It stimulates the expiratory muscles during exercise

Question 5

What does the inspiratory centre do?

Answer 5

It sends out nerve impulses via the phrenic nerve to the inspiratory muscles (diaphragm and external intercostals) to cause them to contract.

Question 6

What are the factors that affect neural control of breathing?

Answer 6

Mechanical factors - proprioceptors, located in the joints and muscles, provide feedback to the respiratory centre to increase breathing during exercise

Baroreceptors - a decrease in blood pressure detected by baroreceptors in the aorta and carotid arteries results in an increase in breathing rate

Stretch receptors - during exercise the lungs are also stretched more, prevent over-inflation of the lungs by sending impulses to the expiratory centre and then down the intercostal nerve to the expiratory muscles

Question 7

What is the order of neural/chemical control for inspiration?

Answer 7

• Receptors
• Medulla oblongata
• Phrenic nerve
• Diaphragm, external intercostals, sternocleidomastoid, scalenes, pectoralis minor

Question 8

What is the order of neural/chemical control for expiration?

Answer 8

• Receptors

• Medulla oblongata

• Intercostal nerve

• Abdominals and internal intercostals